Annual
Globe Amaranth
Gomphrena globosa · Amaranthaceae
Also called: Gomphrena, Bachelor's Button (regional)
Globe Amaranth (Gomphrena globosa) is a low-water annual well suited to Tucson and the low desert. It grows to 1-2 ft tall, 1 ft wide (dwarf types ~6-10 in) in full sun, with a moderate growth rate.
Globe Amaranth at a glance
- Water use
- Low (established)
- Sun
- Full sun; thrives in heat and tolerates Tucson's intense summer sun.
- Mature size
- 1-2 ft tall, 1 ft wide (dwarf types ~6-10 in)
- Growth rate
- Moderate
- Bloom
- Magenta/purple, pink, white, red, orange, lavender (papery clover-like globes), Late spring through fall (one of the best annuals for sustained summer bloom in the low desert, including through monsoon heat).
- Cold hardiness
- Frost-sensitive (USDA 9a-9b); a tender warm-season annual killed by frost. Loves heat.
- Soil
- Well-drained soil of average to poor fertility; tolerates alkaline desert soils. Good drainage is the main requirement.
- Native range
- Central America / Brazil and Panama (tropical Americas)
- Best used as
- Heat-tolerant summer color beds, Borders and edging, Cut flowers, Excellent dried/everlasting flowers (long-lasting papery blooms), Pollinator gardens
- Wildlife
- Attracts butterflies and bees; a reliable nectar source through summer heat.
- Toxicity
- Non-toxic / no significant toxicity reported for humans or pets.
How to grow Globe Amaranth in Tucson & the low desert
Watering
Water 2-3 times weekly to establish, then about once weekly; quite heat- and drought-tolerant once established and dislikes soggy soil. Warm-season annual in Tucson: plant transplants after frost danger passes (Mar-Apr) once soil warms; it loves and bloom strongly through the hottest months and monsoon.
Fertilizer & nutrients
Light feeder. A balanced slow-release fertilizer at planting plus an occasional light liquid feed is plenty; avoid excess nitrogen which reduces flowering.
Pruning & care
Pinch young plants to encourage branching; deadheading is optional since flowers hold color a long time. Shear lightly mid-season if leggy.
Notes
One of the toughest summer-blooming annuals for Tucson, thriving when many flowers fade in the heat. The clover-like blooms dry beautifully for everlasting arrangements. Reseeds modestly.
Sources: University of Arizona Cooperative Extension (Pima County Master Gardeners); AMWUA / Arizona low-desert planting guides; Missouri Botanical Garden Plant Finder